92 Club Car DS quits when Hot

[searobin6]

I have a 92 36 volt series cart that I rewired to run @48 volt with original GE motor.
New Curtis 1205 500 amp controller programed for 48 volt, New PB6 throttle, 400 amp 48 volt solenoid, all new #4 cables, New F & R switch.
Cart runs fine for about twenty minutes then quits once I come off the throttle..
Turn key to off and wait about a minute, turn key on and cart runs again.
Tried changing PB6, solenoid and key switch still having same problem.
Motor seems to get hot when problem occurs.
Controller gets slightly warm, F & R cool, all connections cool.
Solenoid still clicks during problem.